Vacuum insulated container



March 26, 1-935. T, LlTTLEToN 1,995,993 I VACUUM INSULATED CONTAINERFiled June 18, 1934 I NV EN TOR. JZISSL T l 771. a 7'0.

A TTORNEYQS.

Patented Mar. 25, 1935 UNITED STATES" PATENT opt cs (Jorning GlassWorks, poration of New York Application June 18,1934, Serial No. 131,205r Claims. (01. sis-1s) This invention relates to vacuum insulatedcontainers and more particularly to such 'a container which is provided.with an opening at each end.

Vacuum insulated containers, commonly called vacuum bottles, are usuallyconstructed of an inner blank commonly known as an inner piston and anouter blank commonly known as an outer piston, which blanks or pistonsare formed, with 10- bulbous portions and neck portions, the latter.

being sealed together at their outer ends in such a manner that a spaceis formed between the inner and outer pistons which isvevacuated. Thisprovides an eflfective insulation which prevents 15 the contents of thecontainer from being aflected by external atmospheric conditions.Sometimes it is desirable to employ a vacuum insulated container havingan opening at each end in which case neck portions are formed atopposite ends so of the bulbous portions of the pistons and these neckportions are then sealed, together in such a manner that access may behad to the interior of the inner piston from either end of thecontainer.

Such containers are,'however, diiiicult to manuzs i'acture as it is wellknown that after glass has been sealed it must be subjected to anannealing operation in order to release'the strains introduced when theseal is made; The 'annealingof a glass article necessitates subjectingit to a temso perature at or above its strain point and subsequentlycooling it to atmospheric or its service temperature at a predeterminedrate which is cal-- culated in accordance with the physicalcharacteristics of the glass composition from which the 35 article ismade. With hollow Was'sels-it is diillcult to obtain proper balancebetween the cooling rates of the internal and external portions and thisdiinculty is greatly magnified when the internal and external walls areseparated from each. other' as .they are in vacuum'insulated containers.As a a result, double ended vacuum containers of the 'type to which thisinvention relates are subject to breakage during annealing due to thediilerences in expansion between the inner and outer pistons. Moreover,such containers are apt to break in service owing to the fact that whena hot liquid, for instance, is introduced into the inner piston thelatter will become heated and m expansion of the inner? piston will takeplace while the outer piston is yet in its normal state. Hence the sealsbetween the inner and outer pistons are strained and frequently suchstrains exceed the tensile strength of the glass with the i6 result thata crack or actual breakage will occur differs from .that of the glassfrom which destroys the vacuum insulation and the entire container isthen rendered useless. The object of my invention is to overcome thediiliculties heretofore experienced in the manufacture and use of vacuuminsulated containers having openings at opposite ends.

The above and other objects be accomplished by employing my. inventionwhich embodies among its features a vacuum insulated container inwhich'the inner piston is made from 10 a glass having a coefficient ofexpansion which which the. outerpistonismade. a I

Other features embody the use of graded seals between the inner andouter pistons when the diflerences of expansion between them is so greatthat diflicultyisexperienced in eflecting sealing the two diil'erentglasses together.

In the drawing: r

Fig.1isasidevi partlyinsecti'onofs nc-120v uum imuiated con erconstructed in .accordance with my invention; and

Fig. 2 is a fragmentary sectional view of a modifled form of myinvention.

Referring to the drawing in detail, a vacuum container designatedgenerally 10 consists of an inner piston 11 and an outer piston 12 whichare sealed together at opposite ends 13 and 14. The inner piston 11 ispreferably formed froma' glass having a coemcient of expansion which isslightly 3 below that of the outer piston 12 so that in cooling from theannealing temperature the outer piston will be thrownunder a slighttension the inner piston will be thrown under compression. This, then,produces a strained condition in the vessel until the space 15 betweenthe inner and outerpL tons l1 and 12-has been exhausted when atmosphericpressure on the exterior of the outer piston 12 will tend' to collapseit, thus exerting a compressive stress on it and cbunteracting 40 thetensional stresses which it previously pos-i i sessed. Due to thetendency of theatmosphere to expand the inner piston 11 into theevacuated space, any compressional which it previously possessed will becounteracted, at least to some extent, and proper balance will bemaintained with the result that breakage due to strain is less likely tooccur.

In the modification shown in mg." 2. the inner 'j piston 16 of a vacuuminsulated container'desisnated generallyl'l is formed of a glass havingamuch lower coeflicient of expansion than that from which the outerpiston'l8 is made, with the result that a direct and eil'ective sealbetween the two glasses could not be made. Hence, I employ a u gradedseal 19 between the inner and outer pistons and by so doing I am enabledto produce double ended vacuum insulated containers which will meet awidevarietyof service conditions.

While in the foregoing thae has been shown and described the preferredembodiment of my invention, it is to be understood that minor changes inthe details of construction, combination, and arrangement of parts maybe resorted to without departing from the spirit and. scope of myinvention as claimed. What I claim is:

l. A double walled container comprising an inner member and an outermember sealed together at the ends, the latter being formed of materialhaving an expansion coeifiicient which differs from that of the innermember.

2. A doublewalled container comprising an inner member and an outermember sealed together at their ends, the latter being formed of amaterial having a higher expansion coeflicient than that of the innermember. I

v 3. A double walled container comprising an inner member and an outermember, the latter being formed of material having an expansioncoeflicient which differs from that of the inner member and a gradedseal between the inner and outer members.

4. A double. walled container comprising an inner memberand an outermember, the latter being formed of a material having, a higher ex-'pansion coeflicient than that of the inner member and a graded sealbetween the inner and'outer members.

5. A vacuum insulated container comprising an inner piston and an outerpiston both the innet and outer pistons having neck portions at oppositeends, the inner and outer pistons being sealed together at the outerends of the neck portion and being formed of glasses having dil- Ierentcoeflicients of expansion.

6. A vacuum insulated container comprising a glass inner pistonhavingneck portions at opposite ends and an outer piston formed 0! aglass having a'higher coefllcient of expansion than that iromwhich theinner piston is made and having neck portions at opposite ends, theouter ends 01' the neck portions being sealed together.

7. A vacuumins ted container comprising an inner piston or glass, anouter. piston formed 0! a glass having a coeiiicient or expansion whichdiffers from that from which the inner piston is made, both the innerand outer pistons neck portions and graded seals joining the re,spective outer ends of the neck portions 0! the outer and inner pistons.

8. A vacuum insulated container comprising glass inner piston-havingneck portions at opposite ends and an outer piston formed or a glasshaving a higher coefllcient or expansion than that from which the innerpistonis made and having neck portions at opposite ends, graded sealsicining the respective outer ends of the neck portions :of the outer andinner pistons.

E, 'r. urns-ms.

